NFC Tags with Proximity Detection

ABSTRACT

Systems, apparatuses and methods provide for detecting the proximate placement of an external NFC reader to a specific location on a display surface. The display surface can be intended for viewing indicia and enabling interaction with an NFC communication device embedded within the display. A circuit can control an NFC security system that can scan for unauthorized tags affixed to the surface of a display. The NFC security system may be activated by an NFC enabled mobile phone placed proximate to the indicated region for receiving an NFC coded message from the display. An NFC security scan can be performed prior to the mobile phone reading the message from the intended NFC tag in the display. Enabling interactive display modes can allow for making selections indicated on the display or detecting motion gestures across the face of the display.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a division application of U.S. Utility patentapplication Ser. No. 15/679,616 filed Aug. 17, 2017, which is a divisionof U.S. Utility patent application Ser. No. 13/803,041 filed Mar. 14,2013 patented as U.S. Pat. No. 9,767,329 on Sep. 19, 2017, each of whichclaims the benefit of U.S. Provisional Patent Application No. 61/727,907filed Nov. 19, 2012, each of which is incorporated herein by referencein its entirety.

BACKGROUND OF THE INVENTION

Radio frequency identification (RFID) devices, including near fieldcommunication (NFC) enabled RFID devices, are utilized for a variety ofpurposes. Often such devices are formed as tags or labels and can beutilized to associate an object with an identification code or otherdata, such as website data. Such RFID devices may be passive and, uponreceiving a signal, such as an excitation signal from an RFID orNFC-enabled reader, may be energized. The devices can then respond witha desired communication or provide information associated with aproduct, item or service associated with the RFID device.

Specifically, NFC is a data exchange protocol designed to allow devices,including suitably equipped mobile phones and the like, to interact withinfrastructures, such as point of sale terminals and ticket gates ontransportation systems, or RFID devices in the forms of “smart posters”or “touchpoints”, for example. In such situations, bringing an NFCenabled device into proximity of such infrastructure or RFID devices cancause the transmission of data to the NFC enabled device, resulting in,for example, the opening of a web page, the acceptance of a media streamvia Bluetooth or any of a number of other functions.

Often the manner of associating a product, item or service with an RFIDdevice is to physically couple or adhere the RFID device to the productor item, or associate it with advertising relating to the product, itemor service, such as the “smart poster” or “touchpoint” described above.For example, RFID labels may be coupled adhesively to objects or mayotherwise have surfaces that attach directly to objects. RFID tags maybe secured to object in other manners, such as through the use of aplastic fastener, string or other fastening mechanism. Such RFID devicesmay then provide data to NFC enabled devices located or placed proximatethe RFID devices.

Additionally, RFID devices are often associated with the product oritem, or advertising item, in such a manner as to conceal or secure theRFID device. Such methods can provide security against the removal ormisuse of an RFID device. However, in such circumstances, andparticularly with NFC enabled devices designed to convey information toconsumers with NFC enabled mobile phones and devices, there is adesignated area (touchpoint) on an advertisement or product thatindicates information can be obtained if the NFC enabled device isplaced in close proximity to an area associated with the RFID device.However, as it is then known that information can be obtained from suchareas, vandal or pirate RFID devices are often placed in close proximityto the indicated NFC area. The vandal or pirate devices often containdeceptive, misleading, undesired or malicious information. These devicescan be coupled with or adhered to products and items, or advertisementsassociated with those items, leading to inappropriate or maliciousinformation being unknowingly communicated to a user's NFC-enableddevice.

In normal operation, mobile phones that have enabled NFC functionsoperate in NFC reader/writer mode. In this mode, the mobile phonetransmits an NFC tag query consisting of modulated magnetic field pulsesat a carrier frequency of 13.56 MHz. The NFC reader in the mobile phonehas no prior indication that an NFC tag is proximate to the phone untilan NFC tag responds to a query. Therefore, an external NFC reader suchas a mobile phone will consistently transmit NFC interrogation queriesuntil an NFC tag is detected.

SUMMARY

NFC detector circuit systems, apparatuses and methods may provide fordetecting the proximate placement of an external NFC reader to aspecific location on a display surface. The display surface may beintended for viewing indicia and enabling interaction with an NFCcommunication device embedded within the display.

In an exemplary embodiment, a circuit may control an NFC security systemthat scans for unauthorized tags affixed to the surface of a display.The NFC security system may be activated by an NFC enabled mobile phoneplaced proximate to the indicated region for receiving an NFC codedmessage from the display. An NFC security scan may be performed prior tothe mobile phone reading the message from the intended NFC tag in thedisplay.

Other exemplary embodiments may include enabling interactive displaymodes, for example, for making selections indicated on the display ordetecting motion gestures across the face of the display. Suchinteraction may be useful for configuring the contents of the NFC tagbased upon a specific user interaction.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of embodiments of the present invention will be apparent fromthe following detailed description of the exemplary embodiments. Thefollowing detailed description should be considered in conjunction withthe accompanying figures in which:

FIG. 1 is a schematic view of an exemplary embodiment of an NFC detectorcircuit.

FIG. 1A illustrates a display contemplated by the present inventionhaving an authorized NFC tag as well as an unauthorized NFC tag.

FIG. 2 is a schematic view of an exemplary embodiment of an NFC detectorfor controlling the illumination of Light Emitting Diodes (LEDs)integrated into an NFC reading zone.

FIG. 3 is a schematic view of an exemplary embodiment of an NFC foractivating an NFC security security system when an external NFC readeris placed proximate to an NFC reading zone that contains an NFC tag.

FIG. 4 is a schematic view of an exemplary embodiment of an NFC detectorfor activating the NFC security security system when an external NFCreader is placed close to an inductive coil.

FIG. 5 is a schematic view of an exemplary embodiment of an NFC detectorincorporating a counter circuit recording the number of instances thatan external NFC reader is placed proximate to a receiving inductive coilof an NFC detector.

FIG. 6 is an exemplary flowchart showing an order of operations for anNFC security system.

DETAILED DESCRIPTION

Aspects of the invention are disclosed in the following description andrelated drawings directed to specific embodiments of the invention.Alternate embodiments may be devised without departing from the spiritor the scope of the invention. Additionally, well-known elements ofexemplary embodiments of the invention will not be described in detailor will be omitted so as not to obscure the relevant details of theinvention. Further, to facilitate an understanding of the descriptiondiscussion of several terms used herein follows.

As used herein, the word “exemplary” means “serving as an example,instance or illustration.” The embodiments described herein are notlimiting, but rather are exemplary only. It should be understood thatthe described embodiments are not necessarily to be construed aspreferred or advantageous over other embodiments. Moreover, the terms“embodiments of the invention”, “embodiments” or “invention” do notrequire that all embodiments of the invention include the discussedfeature, advantage or mode of operation.

Generally referring to FIGS. 1-6, exemplary embodiments disclosed hereinmay describe NFC security systems, sometimes referred to as NFC WatchDog systems. In some exemplary embodiments, queries transmitted by theexternal NFC reader in reader/writer mode can be used to sense when amobile phone is placed proximate to a specific location on a displaysurface using NFC detector circuitry.

An exemplary NFC security system may include an NFC reader, a securitycontroller 111 and an inductive coil with impedance matching circuits.Functions of an NFC security system may be to detect unauthorized tags,disable such tags and alert maintenance personnel of a problem.

The detection of unauthorized tags 216 may be achieved by an NFC readercomponent transmitting NFC interrogation commands to an inductive coilof a detector. The inductive coil may distribute magnetic energy overthe surface of the display that is being interrogated for unauthorizedtags. A security controller 111 of an exemplary NFC security system maynot perform interrogation on a constant basis, so that it may notinterfere with a communication channel of an external NFC reader and anNFC device such as an NFC tag. The security controller 111 may activatereading on regular intervals or conditionally upon the state of a signalline, such as from another controller or sensor. The NFC detector of thedetector circuit may be configured to send a signal to the NFC securitysystem when a phone is placed proximate a specific location on thesurface of a display.

Exemplary embodiments may require less complex circuit design than othersolutions utilizing an NFC reader circuit. In some exemplaryembodiments, the major elements of the NFC detector circuit may includean inductive receiver coil, an RF demodulator and a threshold detector.The NFC detector circuit may not decode the data signal of an externalNFC reader in order to detect its proximate placement on a displaysurface. Additionally, the NFC detector circuit may be designed only forreceiving RF signals and may not transmit RF signals, unlike an NFCreader. As such, multiple NFC detectors or detector circuits may beintegrated into a display system without interfering with acommunication channel of an external NFC reader or an intended NFCcommunication device such as an NFC tag.

In an exemplary embodiment, a display may include two or more NFCdetector circuits positioned apart over the display surface so thatusers may indicate choices using placement of the mobile phone based ondisplay indicia. For example, if a user of the display places anexternal reader such as a mobile phone directly over one of the NFCdetectors of a detector circuit, then the display may indicate theuser's selection, such as departure information. In the same example, amobile phone placed over another NFC detector may indicate arrivalinformation is being desired. Once a selection has been made by theuser, the NFC tag memory may be formatted with the appropriate NDEFmessage, which in this example may include a link to either the arrivalor departure information.

In another exemplary embodiment, a display may include multiple NFCdetectors embedded over a surface. The display system may detect whenthe user moves the mobile phone along a path recognized by the displaysystem, which may be referred to as a gesture, such as, for example,following a circular path along display indicia. When a gesture isrecognized by the display system, a custom NFC message may be preparedfor the user, which may be read by the NFC enabled mobile phone.

Exemplary embodiments may reduce power consumption in systems thatutilize the NFC detector to control the active state of NFCtransceivers, such as NFC readers and NFC peer-to-peer mode devices. Aninternal NFC reader 212A used in the NFC security system may want totransmit enough power to interrogate unauthorized tags that could beaffixed to the display. The power for the interrogation function may beup to 4 watts, depending on the desired operating range and size of thetransmitting NFC coil. Utilizing an NFC detector to control the activestate of an NFC reader may reduce power consumption, for example bylimiting interrogation functions to necessary conditions, such as whenan external NFC reader is brought close to the display.

Additionally, utilizing the NFC detector for lower power consumption mayenable a display system to operate from battery power instead of a mainconnection. In an exemplary embodiment, the display system may use abattery as backup power for situations in which the main power has beeninterrupted.

In another exemplary embodiment, the NFC detector may control operatingmodes of an NFC peer-to-peer mode reader, which may function to transmitNFC messages via Simple NDEF Exchange Protocol (SNEP) to the externalNFC reader. In this exemplary embodiment, the display system may bebattery powered, which may require that the peer-to-peer reader beactivated only when an external NFC reader is present.

Referring now to exemplary FIG. 1, a schematic view of an exemplaryembodiment of an NFC detector circuit may be shown. The elements of thedetector circuit may include a near field inductive receiver coil 102with impedance matching element 104, a demodulator 106, and a thresholddetector 108.

The inductive receiver coil 102 may include a distributed inductoradapted to be receptive to alternating magnetic fields in the vicinityof the coil. The capacitor 104 may form an impedance matching circuitbetween the inductive receiver coil 102 and a transmission line 110,such as, for example, a 50 ohm transmission line.

The impedance matching circuit may be adapted to enable a low losstransmission of signal energy between the inductive receiving coil 102and the transmission line 110, which may be connected to other circuitsof the NFC detector.

The capacitor 104 in FIG. 1 is only one exemplary embodiment of animpedance matching circuit; other circuit configurations may be possiblewhich may, for example, increase the bandwidth across the frequency bandbut require the use of more complex circuitry for implementing theimpedance matching circuit. Such impedance matching circuits may includeany impedance matching circuit known in the art.

In this exemplary embodiment, when an external NFC reader is proximateto the NFC detector of the detector circuit, an RF signal ontransmission line 110 may be received by the demodulator circuit 106 forrecovery of the original data signal without an RF carrier wave. Thedemodulator 106 in FIG. 1 can be a diode envelope detector, used, forexample, because of relatively simple circuit and low power consumption.However, if better signal discrimination or input filtering is desired,any other demodulator circuit known in the art may be implemented withthe associated design trade-off in circuit complexity and powerconsumption. The output signal of the demodulator 106 may include DCvoltage pulses 116 which may travel via the transmission line 112 to thethreshold detector circuit 108.

The threshold detector circuit 108 may drive a two state output signal,normally in the “disabled” state, to the “enabled” state when the outputvoltage from the demodulator exceeds the “enabled” or high thresholdvoltage point. Separating the high and low threshold levels of thethreshold detector 108 may form a hysteresis function, such that the“enabled” output state cannot be reset back to the “disabled” state,until the input voltage is lower than the “disabled” threshold voltagepoint. As such, the output state of the threshold detector may notoscillate if the input voltage oscillates around either voltagethreshold point. The threshold detector 108 in exemplary FIG. 1 can be alow power Schmitt trigger circuit. The Schmitt trigger circuit may beutilized as it is a well-documented circuit commonly used in manycircuit applications; therefore the design and implementation of aSchmitt trigger is not described in detail here. However, otherthreshold detectors known in the art may be implemented, as desired. Theoutput of threshold detector 108 may drive the two state output signalthrough the transmission line 114 to digital output circuits for thehost system 118. The digital output 118 to the host system may beimplemented with necessary circuitry to buffer or latch the output stateof the NFC detector for immediate or later use by the host system inputcircuitry.

FIG. 1A of the present invention illustrates a display 212 having bothan authorized NFC tag 218 and an unauthorized tag 216. The presentinvention contemplates that the internal NFC reader 212A of the detectorcircuit 302 detects an unauthorized tag 216 applied to the display 212and creates a signal in order to disable the unauthorized tag 216.

FIG. 2 is a schematic view of an exemplary embodiment of an NFC detectorof a detector circuit that may control the illumination of LightEmitting Diodes (LEDs) integrated into an NFC reading zone. The circuitmay be adapted to indicate to the user that the external NFC readerdevice 214 has been placed in a proper or desired region for reading theintended NFC tag. The inductive element of the NFC detector and the LEDsmay be located proximate to the NFC reading zone. Other circuit elementsmay not have critical placement with respect to the display surface andmay be placed where best suited or desired. The NFC detector 202 in theexemplary circuit may drive the voltage of the control line 220 toeither the “enabled” state value when an external NFC reader isproximate to the NFC detector, or to the “disabled” state value when noexternal NFC reader is proximate to the detector. The LED driver circuit204 may adjust the voltage and current source on line 222 relative toground 210 to the appropriate condition to illuminate the LEDs 206 and208 inside the display located near the NFC reading zone.

FIG. 3 is a schematic view of an exemplary embodiment of an NFC detectorof a detector circuit that may activate an NFC security system when anexternal NFC reader, such as a mobile phone, is placed proximate to anNFC reading zone that contains an NFC tag. The NFC detector circuit 302may drive the line 310 with an output voltage level signifying the“enabled” state to the security system 304. Upon sensing the “enabled”state voltage on the wakeup control line 310, the security system mayperform an NFC inventory command with an internal NFC reader 212A. Theinternal NFC reader 212A may transmit NFC air protocol commands throughthe cable 312 to the matching network 308 and then to the transmittingcoil 306. If the security system discovers an unauthorized tag, thenappropriate actions may be taken, such as, for example, disabling thetag or sending a help request to maintenance personnel. When the NFCsecurity function is complete, the system may transition to a sleep modefor minimal power consumption. Subsequently, the NFC detector circuitmay remain idle for a specified time, to allow the external NFC readerto transfer contents of the authorized NFC tag without interference fromthe NFC security system.

FIG. 4 is a schematic view of an exemplary embodiment of an NFC detectorthat may activate the NFC security system when an external NFC reader,such as a mobile phone, is placed close to a common inductive coil 408.The inductive coil may include a common element to both the detector andthe security system. The use of a common coil may be such that eachcircuit establishes an exclusive connection to the cable 412 thatconnects to the common coil 408. A “detect” state and a “security” statemay be used for selecting a connection to a common NFC coil 408. Theinitial and nominal state for the system may be the “detect” state. Whenthe display system is in the “detect” state, the NFC detector circuitmay have priority control of the common NFC coil 408, while the securitysystem may be disconnected from the common coil 408 and configured to alow power sleep mode. The NFC detector may continually monitor forsignals from an external NFC reader, such as a mobile phone. Upondetecting a signal from an external reader, the system may transition tothe “security” state. In the “security” state, the NFC detector maydisconnect from the common NFC coil 408 by open circuiting theconnection to the cable 412. The NFC detector may then drive the voltageof the wake up line 406 to the “enabled” state. The security system maydetect the “enabled” state of the wake up line 406 and may transition tothe “security” state. Upon transitioning to the “security” state, thesecurity system may connect the common NFC coil 408 by switching thecircuit connection of the system to cable 412 from an open circuit to ashort circuit. The security system may then issue NFC inventory commandsto the common coil 408 to check for unauthorized tags affixed to thedisplay. If unauthorized tags are affixed to the display, the securitysystem may perform actions such as attempting to disable theunauthorized tag or signaling a request for maintenance personnel toremove the unauthorized tag. Upon completion of the security operation,the security system may open the circuit connection to cable 412, maysignal to the NFC detector that the security mode is complete, and maythen transition to the low power operating state. The system state maythen be returned to a “detect” mode. Upon switching from “security”state to “detect” state, the NFC detector circuit may remain idle for aspecified time to allow the external NFC reader to transfer the contentsof the authorized NFC tag without interference from the NFC securitysystem.

FIG. 5 is a schematic view of an exemplary embodiment of an NFC detector502 that may incorporate a counter circuit 504 that may record thenumber of instances that an external NFC reader, such as a mobile phone,is placed proximate to a receiving inductive coil of an NFC detector.The stored value of the counter circuit may be used, for example, todetermine metrics for the effectiveness of the display. The signal line510 may be routed to other functions 506 that sense the state of the NFCdetector output signal. The other functions 506 may include, forexample, an NFC security system or an interactive display system asdescribed above.

FIG. 6 is an exemplary flow chart describing aspects of the NFC securitysystem. In this exemplary embodiment, time 602 may represent any timeafter an NFC security system is implemented and/or triggered. The systemcan include sensors 604 which work to detect any undesired or rogue NFCsignals. Thus, if sensors 604 are active and do not detect any roguesignals, the system may go into sleep 606 mode. If sensors 604 areactive and detect a rogue signal, a desired response action 610 may betaken. The response action can include blocking the rogue signal ordestroying the rogue device. If the action 610 is successful, the systemcan return to sleep 606 mode. If the action is unsuccessful, the systemmay try to take the desired action 610 again, or a signal may bedispatched to appropriate personnel. As can be appreciated by the above,any other courses of action using other components may also be utilized.

The foregoing description and accompanying figures illustrate theprinciples, preferred embodiments and modes of operation of theinvention. However, the invention should not be construed as beinglimited to the particular embodiments discussed above. Additionalvariations of the embodiments discussed above will be appreciated bythose skilled in the art.

Therefore, the above-described embodiments should be regarded asillustrative rather than restrictive. Accordingly, it should beappreciated that variations to those embodiments can be made by thoseskilled in the art without departing from the scope of the invention asdefined by the following claims.

What is claimed is:
 1. A method of implementing a NFC security systemcomprising: providing a display, the display having a NFC securitysystem having a security controller, an NFC reader, an inductive coil,and at least one detector; placing an external NFC reader near thedisplay to read at least one NFC tag; triggering the system; detecting arogue signal from at least one unauthorized NFC tag; and determining anaction for disabling the at least one unauthorized NFC tag.
 2. Themethod of claim 1, where the action is generating an alarm to remove theunauthorized NFC tag.
 3. The method of claim 1, wherein the methodfurther comprises blocking the rogue signal from the unauthorized NFCtag after the step of detecting.
 4. The method of claim 1, wherein themethod further comprises destroying a rogue device after the step ofdetermining.
 5. The method of claim 1, wherein the method comprising thefurther step of failing to detect at least one rogue signal, such thatthe system enters a sleep mode.
 6. The method of claim 1, wherein the atleast one detector is positioned apart over a surface of the display. 7.The method of claim 1, wherein the at least one detector is embedded inthe display.
 8. The method of claim 1, wherein the NFC reader of thedisplay transmits enough power to interrogate unauthorized tags.
 9. Themethod of claim 1, wherein the inductive coil includes a common elementto both the at least one detector and the NFC security system.
 10. Themethod of claim 9, wherein the common element is a common coil.
 11. Themethod of claim 1, further comprising taking the action again if theaction is unsuccessful.
 12. The method of claim 1, wherein the externalNFC reader is a mobile phone.
 13. The method of claim 1, wherein theinductive coil comprises impedance matching circuits.
 14. The method ofclaim 1, wherein the system further comprises at least one sensors. 15.The method of claim 1, wherein the security controller activated readingconditionally upon a state of a signal line.
 16. The method of claim 15,wherein the signal line is routed to functions that sense the state of aNFC detector output signal.